Reply
Authors: Shantha Ram Valainathan, Maxime Ronot, Valérie Vilgrain, Pierre-Emmanuel Rautou
Journal: Hepatology (2023)

We read with great interest the letter by Liu and colleagues commenting on our recent article on CT features and liver surface nodularity in patients with portosinusoidal vascular disorder (PSVD).1 Firstly, regarding the definition of the size of segment IV, surprisingly there is no consensual definition either using a binary or a continuous approach on CT. Existing cut-off values have been described with ultrasound.2 In our study, we measured the size of segment IV on a contrast-enhanced CT (axial plane) between the gallbladder and the interlobar fissure, perpendicular to the long axis of the gallbladder. The visual impression was based on the assessment of the overall volume of segment IV, with a particular interest in the width of the interlobar fissure, the contact or not with the gallbladder, and the width of the preportal fatty area, posterior to segment IV. Secondly, Liu and colleagues rightfully remind us that patients with PSVD rarely develop hepatocellular carcinoma. This is the reason why we performed—as part of our study—sensitivity analyses restricting the analysis to patients without HCC.1 These analyses gave similar results to those obtained in the overall cohort, namely a 90% (95% CI, 0.79–0.97) specificity of LSN <2.5 and normal-sized or enlarged segment IV for PSVD. Thirdly, regarding the selection process of the variables entered into the multivariate binary logistic regression analysis, as described in the statistical analysis paragraph of our study,1 we included CT features having a different prevalence between patients with PSVD and with cirrhosis at univariate analysis, with alpha-level <0.05 after Bonferroni's adjustment for both readers and with data available for all patients. Fourthly, indeed, our team recently showed that (Liver Stiffness Measurement) (LSM) <10 kPa strongly suggests PSVD in patients with signs of portal hypertension.3 The present study was not designed to compare Liver surface nodularity (LSN) to LSM, so only 34 and 39 patients with PSVD and cirrhosis, respectively, had both valid LSN Liver surface nodularity and LSM. This is the reason why these data were not mentioned in this manuscript. Lastly, as requested by Liu we provide here, in Figure 1, receiver operating characteristic curve and calibration for the multivariable model, showing that the accuracy of the multivariable model was very good.FIGURE 1: ROC curve and calibration of the multivariable model in the test cohort (A, C) and validation cohort (B, D). (A and B) ROC curves. (Cand D) Calibration. Violin plots represent the density of patients according to the probability of PSVD or of cirrhosis assessed using the multivariable model we developed. Abbreviation: PSVD, portosinusoidal vascular disorder ROC, receiver operating characteristic.AUTHOR CONTRIBUTIONS Shantha Ram Valainathan and Pierre-Emmanuel Rautou: drafting the article. Maxime Ronot and Valérie Vilgrain: critical revision for important intellectual content. Shantha Ram Valainathan, Maxime Ronot, Valérie Vilgrain, and Pierre-Emmanuel Rautou: final approval of the version to be published. FUNDING INFORMATION Pierre-Emmanuel Rautou's laboratory receives financial support from the "Institut National de la Santé et de la Recherche Médicale" (ATIP AVENIR), the "Agence Nationale pour la Recherche" (ANR-18-CE14-0006-01, RHU QUID-NASH, ANR-18-IDEX-0001), "Émergence, Ville de Paris", Fondation ARC and from the European Union's Horizon 2020 research and innovation program under grant agreement No 847949 (DECISION). CONFLICT OF INTEREST All authors have nothing to declare.